Contamination of environment by radionuclides in territories under urboecosystem conditions is actual problem. The search of new express methods for radioactivity determination of environment is important task of research. In present work it was shown that mosses are bioindicators of radioactive contamination, because they accumulate radioactive substances in high concentrations. Using of bryoindication methods are promising techniques for the assessment of the contamination of ecosystems with radionuclides. The use of epiphytic mosses is the most efficient technique for assessing the contents of radionuclides in the surface air layer. The epiphytic moss (Pylaisia polyantha) growing in different zones of the city of Rostov-on-Don, was used for the radioactivity biomonitoring of urbosystems. The accumulation features of radionuclides in the epitaphic pylaisiella moss (Pylaisia polyantha) in the territory of the city of Rostov-on-Don have been considered. It was shown that Pylaisia polyantha is effective indicator of radioactivity for biomonitoring. The activity concentration of 137 Th were revealed. These were primarily the zones with both industrial and traffic loads and the motor transport zones. The results of investigation showed that the epiphytic moss (Pylaisia polyantha) can be used as indicator of radioactivity pollution in different polluted zones.